5.37.10.1 DL Data Burst Size marking

The Data Burst Size may be provided to the NG-RAN in the downlink GTP-U header by the UPF in order to assist radio resource management. As described in clause 6.1.3.27.5 of TS 23.503 [45] the PCF may include a Data Burst Size Marking Indication within a PCC Rule to request the UPF to identify and mark the Data Burst Size of the data burst for the corresponding QoS Flow. The PCF also includes the DL Protocol Description received from AF.

Based on the Data Burst Size Marking Indication in a PCC Rule, the SMF instructs the UPF to identify and mark the Data Burst Size of the data burst in downlink for the corresponding PDR. The SMF may provide the UPF the Protocol Description received in the PCC Rule.

According to the Data Burst Size Marking Indication and DL Protocol Description from the SMF, the UPF identifies in the first DL packets of the data burst the Data Burst Size carried in an N6 RTP Header Extension/ transport protocol header as defined in TS 26.522 [179]. The UPF sends the identified Data Burst size to NG-RAN in the downlink GTP-U header of the first PDUs of the data burst.